Apparatus and methods for inserting an implant

ABSTRACT

A system and method for inserting an implant into a cavity is disclosed, which may include advancing an implant insertion instrument toward a pair of adjacent bodies, the implant insertion instrument having two opposed ramps, wherein each ramp has a distal tip and wherein the longitudinal axes of the opposed ramps are separated by an initial angle; inserting the distal tips of the opposed ramps between the adjacent bodies, thereby creating an initial interbody cavity between the adjacent bodies; expanding the interbody cavity while maintaining the initial angle between the longitudinal axes of the opposed ramps; placing the implant in a final location between the adjacent bodies; transferring a compressive force urging the adjacent bodies together from the opposed ramps to the implant; and extracting the implant insertion instrument from the interbody cavity.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/246,297, filed Sep. 27, 2011, which is a divisional of U.S. Pat. No.8,062,303, filed Jan. 12, 2007, which claims the benefit of U.S.Provisional Patent Application No. 60/822,613, filed Aug. 16, 2006, theentire disclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This present invention is directed to methods and apparatus forinterbody distraction and implant/transplant insertion.

The spine surgical community and surgical literature acceptintervertebral devices (commonly known as interbody spacers, andallograft transplants) as part of the art and routine practice in thereconstruction of collapsed intervertebral disc spaces. Surgeons insertthese interbody devices/transplants to facilitate bone fusion in betweenand into the contiguous involved vertebrae. This fusion creates a newsolid bone mass, which acts to hold the spinal segment at an appropriatebiomechanically restored height as well as to stop motion in a painfulsegment of the spine. Items surgically placed in these involvedinterbody regions can thus stimulate interbody bone in-growth such thatthe operated anterior spinal segments heal into a contiguous bone mass;this means that a fusion occurs. Further, the surgical community usessuch man-made implants or biological options to provide weight bearingsupport between adjacent vertebral bodies, and thereby correct oralleviate a variety of clinical problems. In this regard, surgeons useintervertebral spinal implants/transplants for surgical therapy fordegenerative disc disease (DDD), discogenic low back pain,spondylolisthesis, reconstruction following tumor or infection surgery,and other spine related maladies requiring surgical intervention.Herein, a gap separating two adjacent bodies is referred to as aninterbody cavity. A gap separating two adjacent vertebral bodies isreferred to as an intervertebral cavity.

In many implant designs, a relatively hard or sturdy implant constructis formed from a selected biocompatible material such as metal, ceramic,or carbon fiber-reinforced polymer. This implant construct often has apartially open or porous configuration and is coated or partially filledwith a selected bone ingrowth-enhancing substance, such as harvestedbone graft supplied from the patient, human donor allograft bonetransplant material supplied by a tissue bank, genetically cultivatedbone growing protein substitutes, and/or other biological/biochemicalbone extenders. Such devices, when implanted into the intervertebralspace, promote ingrowth of blood supply and grow active and live bonefrom the adjacent spinal vertebrae to inter-knit with the implant,thereby eventually immobilizing or fusing the adjacent spinal vertebrae.Such implants also commonly include a patterned exterior surface such asa ribbed or serrated surface, or screw thread geometry, to achieveenhanced mechanical locking with the adjacent vertebrae during the boneingrowth/fusion process.

The inventory of available surgical devices has expanded to includemachined, transplantable allograft bone spacers. Bone Banks and tissueprocessors are able to precision-engineer donated human bone to specificvertebral interbody milled dimensions most likely to fit into theaffected intra-discal zones. For many spine surgeons these biologicalsolutions may prove a better option for a particular patient than theuse of man-made materials.

The intervertebral or interbody implants of these general types haveachieved a significant degree of clinical success. Notwithstanding thissuccess, a variety of problems arise in connection with surgicalinterbody implant placement. Surgeons can have difficulty with theimplantation process because of individual pathology, deformity,anatomical space restraints, or implant material limitations.

Often, implant placement proves a difficult and time-consuming procedurewhen the adjacent vertebrae's soft tissue support elements degenerate,causing collapse of the spaces between the vertebrae. This degenerativecondition coupled with compromised adjacent tissues, nerves andvasculature may impede physical and visual access to the intervertebralspace.

Spine surgery of this type may require removal of the remaining discmaterial, release of the contracted soft tissues around the disc space,and some degree of distraction or pulling apart of the adjacentvertebrae in an attempt to restore disc space height, realign the spine,and indirectly decompress the nerve roots exiting the spine posteriorlyat that level. This distraction procedure has traditionally required theuse of several surgical distraction instruments, which may increase theprocedure's overall complexity, intensify the invasiveness of thesurgical procedure, and possibly lead to iatrogenic vascular andneurosurgical injuries which can cause intraoperative surgicalcomplications. At the same time, use of multiple instruments may limitthe surgeon's manual access and clear visualization of the involvedintervertebral space.

After the surgeon removes the disc material, he has made a cleanaperture in which to place the device. Typically the surgeon grasps theinterbody spacer with a special pliers-like tool and places it at themouth of this opening. At this juncture, the surgeon typically usesextreme force as he hammers on the top part of the tool so that theimplant finds its final placement. This hammering technique vectorsenormous shear forces through the spacer. The actual implants havematerial and engineering limitations which may cause the implant tofracture, shear, or break apart as a result of these forceful insertionmoments. In addition, some implant designs require materials which donot tolerate well the use of impaction-type forces necessary to advancethe implant into the intervertebral space.

A variety of intervertebral implant insertion instruments have beendeveloped in recent years as a result of efforts to simplify surgicaldistraction of the intervertebral space while facilitating placement ofthe implant therein. See, for example, U.S. Pat. Nos. 6,755,841;6,478,800; and 6,652,533; and U.S. Publication No. 2005/0165408 whichdisclose instruments for advancing an intervertebral implant between apair of pivotally mounted distraction levers used to engage and distractadjacent vertebral structures. In these designs, the advancing movementof the implant is accompanied by wedged separation of the distal endtips of the levers which are engaged with and thereby separate ordistract the adjacent vertebral structures.

While such implant insertion instruments provide a significantimprovement in the art, the implant is not always safeguarded againstsubstantial and potentially undesirable compression and shear forcesduring such advancing displacement between the pivoting distractionlevers. In addition, these instruments have not provided a simplemechanism for quickly and easily retracting the distal end tips of thelevers from the distraction space following intervertebral placement ofthe implant. Moreover, these instruments have not provided orcontemplated the capability for use with implants of different sizes,such as implants having different height dimensions which may beindicated by specific patient requirements, without altering theinsertion angle of the distal end tips of the distraction levers. Inthis regard, an amplified increase in the tip insertion angle,associated with implantation of a significantly taller implant, canundesirably increase the complexity and difficulty of the surgicalimplantation procedure.

There exists, therefore, a significant need for further improvements inand to intervertebral implant insertion instruments and relatedintervertebral implants for use therewith, particularly with respect toquickly and easily distracting the intervertebral space for facilitatedplacement of an implant having a range of different heights, forsafeguarding the implant against compression and shear forces duringintervertebral distraction, and further for quickly and easily releasingthe implant from the insertion instrument within the intervertebralspace.

SUMMARY OF THE INVENTION

According to one aspect, the present invention provides: an instrumentfor inserting an implant which may include at least two opposed rampshaving an initial angle between the respective longitudinal axesthereof, each ramp having a proximal and a distal end; at least onedistraction guide disposed between the opposed ramps and mobile withrespect to the ramps along the longitudinal axes thereof, whereinadvancement of the distraction guide distally along the longitudinalaxes of the ramps is operable to separate the ramps while holding theinitial angle between the two ramps at least substantially constant.

According to another aspect, the present invention provides a method forinserting an implant into a cavity which may include advancing animplant insertion instrument toward a pair of adjacent bodies, theimplant insertion instrument having two opposed ramps, wherein each ramphas a distal tip and wherein the longitudinal axes of the opposed rampsare separated by an initial angle; inserting the distal tips of theopposed ramps between the adjacent bodies, thereby creating an initialinterbody cavity between the adjacent bodies; expanding the interbodycavity while maintaining the initial angle between the longitudinal axesof the opposed ramps; placing the implant in a final location betweenthe adjacent bodies; transferring a compressive force urging theadjacent bodies together from the opposed ramps to the implant; andextracting the implant insertion instrument from the interbody cavity.The distraction guide and ramp may be provided as separate parts thatmay be reversibly assembled to one another as needed. Alternatively, amodule including one or more distraction guides and one or more rampsmay be provided as a substantially permanent assembly.

One or more embodiments of the invention have applicability when a spinesurgical team access the spine from a retro peritoneal or anteriorlateral approach. The spine surgeon may initially remove disc materialfrom the anterior or anterior lateral involved disc space, and may theninsert an instrument embodying one or more aspects of the inventionbetween two human spinal vertebrae to distract or separate the opposingvertebrae. The surgeon may then place a spinal implant and or allogenictransplant of specific dimensions and geometry into the openedintervertebral space. One or more aspects of the invention may bedirected to an instrument having novel ramp segments for safe andreliable distraction of the bone structures in a manner accommodating arange of different implant and transplant sizes. Thus, an instrument inaccordance with one or more embodiments of the present invention may beemployed to gently insert the intervertebral device or transplant safelyand with relatively little force.

In accordance with one or more aspects of the invention, an improvedinsertion instrument that may be placed through an anterior or anteriorlateral surgical wound, may operate to distract adjacent bonystructures, such as spinal vertebrae, and to insert an implant into thedistracted and evacuated disc space. The insertion instrument mayinclude an elongated inserter body having a modular and a removabledistal end that may be coupled to a distraction guide which may includea pair of clamp jaw components with tall side walls that may beconfigured to support, carry, grasp and/or thread into, and release theimplant, in combination with a pair of sliding trapezoidal ramped wedgesthat may be mounted into the distraction guides so that as the wedgestravel along the guide, the wedges may engage and distract the deviceand consequently distract the adjacent spinal vertebrae or likestructures. The side walls of the distraction guides, which may be tall,may have elongated grooves cut at an angle corresponding to the angle ofthe cephalad and caudal faces of the implant. In one or moreembodiments, the grooves may have a first portion which may beperpendicular to the side walls and/or a second portion which may be atan non-perpendicular angle relative to the side wall, thus forming a“FIG. 4” type shape. This groove may extend from the proximal end to thedistal end of the distraction guide. In one or more embodiments, theside walls of the distraction guide may define a height dimensionslightly less than a corresponding height dimension of the implantcarried thereby.

In one or more embodiments, the distal end of the inserter body may beadapted to enable removable mounting of the distraction guide includingthe clamp jaw components of selected size and shape for supporting andretaining the implant. Likewise, one or more further embodiments of thedevice may use a threaded rod placed through the center of the implantdelivery handle that is designed to engage or mate to a threaded holefound anteriorly or off axis through the implants. Likewise, one or morefurther embodiments of the device may use non threaded prominences(protrusions) placed centrally on the jaw components or along the radiusof the clamp jaws that are designed to engage or mate through theimplants to non threaded holes, slots, grooves found anteriorly,anterior laterally or other possible off axis interfaces into or throughthe implant/transplant. In one or more embodiments, the inserter bodyand jaw components may define a keyed interlock assembly. The jawcomponents may be carried by arm members that are mounted so as to slidefrom the proximal to distal instrument ends onto the inserter body andmay be spring loaded such that default displacement may be directed in alaterally outward direction, thereby spreading the jaw componentssufficiently for to release the implant. In one or more embodiments, thearm members may be retained in a laterally inboard position by a tubemechanism for normal clamp-lock retention of the implant. In one or moreembodiments, the tube mechanism may include a square surface attached toa threaded member that may be engaged at the distal end. This threadedmember may be engaged with an external thread at the distal end of theinserter body. As the threaded member rotates, the sliding mounted tubemechanism may move along the exterior of the inserter body and the armmembers. In one or more embodiments, the arm members have angled faceson their outward surfaces, such that the angled faces may be engaged bythe interior surface of the tube member, thereby allowing the armmembers to be forced in and out, depending on the position of the tubemember. In one or more embodiments, when the tube member is in theproximal position, the arm members may be pressed outward by theinternal springs, thus releasing the implant. However, when the threadedmember is moved to a more distal position, the corresponding clamp jawcomponents may be forced inward, thereby supporting and retaining theimplant.

In one or more embodiments, the distal-end ramp segments of the twodistraction ramps may include distal-end distraction tips shaped to fitbetween adjacent spinal vertebrae. The distraction guides may beadvanced between the ramps to distract the distal-end ramp segments andthe vertebral structures engaged thereby, and also advance the implantinto the resulting distracted intervertebral space. The distractionguide(s) may define a height dimension slightly less than the thicknessof the implant being advanced by the guides. However, the distractionguide may cooperate with the distal-end ramp segments to provide acombined height dimension that is slightly greater than the implantheight to prevent compression and shear force loading of the implantduring advancement thereof between the distraction ramps. The outersurfaces of the distal-end ramp segments may be roughened or serrated ina manner that may be effective to grip the adjacent endplates of thevertebral bodies in order to prevent movement of the ramps in relationto the bone. Furthermore, an elongated groove extending from the distalends of the ramps to the point just offset from the proximal ends of theramps may be located on each of the outer lateral walls of the ramps.These grooves may include a first portion which may be perpendicular tothe side walls and a second portion which may be oriented at an anglerelative to the side wall, thus forming a “FIG. 4” type shape. Theabove-described ramp grooves may have an orientation opposite thosewhich may be present on the interior side walls of the distractionguides. The grooves on the ramps may engage the grooves on thedistraction guides, thereby enabling the ramps to slide with respect tothe distraction guides.

In one or more embodiments, the above described geometric interfacebetween the ramps and the distraction guides may operate to transfer thecompressive force load from the vertebral bodies through the ramps andonto the distraction guides. The preferably perpendicular portion of thegroove may enable the ramps to slide along the distraction guides whilemaintaining a specific lordotic angle throughout the insertion process.In one or more embodiments, the endplates of the vertebral bodies may beheld at this specified lordotic angle while being distracted axiallyduring the implantation. With the tube mechanism in the distal positionand the clamp jaws pressed inboard, the angled portions of thedistraction guide may be moved to a laterally inward position, therebycausing the ramps to be maximally distracted for a given position of thedistraction guides with respect to the ramps along the longitudinal axisof the insertion instrument.

In one or more embodiments, when the tube member is in the distalposition, and the distraction ramps are at their greatest height inrelation to the implant, the ramps can be slid along the guides andmoved into an advanced position in which the distal-end distraction tipsof the ramp segments project beyond the implant and the distractionguide. In one or more embodiments, the distal-end distraction tips maybe configured for facilitated slide-fit reception into theintervertebral space, and may include stops defining an insertion limitor depth guide. The implant carried by the clamp jaw components at thedistal end of the inserter body may then be advanced, such as by impactadvancement, ratchet advancement, and/or threaded screw likeadvancement, between the distraction ramps in a distal direction towardthe intervertebral space. Such advancement of the implant may beaccompanied by distraction or spreading of the distraction ramps byengagement with the distraction wedge, and by corresponding distractionof the intervertebral space. Implant advancement may continue until theimplant is positioned within the intervertebral distraction space. Inone or more embodiments, the combined height of the distraction rampsand guide may be greater than the thickness of the implant. One or morefurther embodiments of the distal portion of the implant insertiondevice may terminate in two flat metallic tabs oriented superiorly andanteriorly to the respective vertebral bodies which insert into thecavity and have for their purpose the distraction of vertebral bodiesand further act to gently transfer the final compressive load to theimplanted device. Therefore, the implant may experience little or noforce during the insertion process.

In one or more embodiments, once the implant is suitably advanced intothe distraction space between the adjacent spinal vertebrae, the rampsmay be positioned such that the tang portion of the ramps may beadjacent to the implant, with no portion of the ramps being locatedbetween the implant and the vertebral bodies. However, at this stage,the compressive force from the vertebral bodies may still be supportedby the ramps and the distraction guides. The tube member may then beretracted into a proximal position by suitably rotating the knob,thereby allowing the arm members to slide laterally outward, which maythereby release the implant from the clamp jaws. As the distractionguides move laterally outward along with the arm members, the angledfaces of the ramps may slide down the angled surface of the outwardlymoving distraction guides, thereby decreasing the combined height of theramps until the vertebrae-contacting surfaces of the ramps are separatedby a distance that is less than the thickness of the implant. Thismovement may gradually transfer the compressive force urging theadjacent vertebral bodies together from the ramp tips to the implant. Inone or more embodiments, the transfer of the compressive load off theramps may be operable to enable the ramps to be easily removed from theintervertebral cavity without disturbing the placement or positioning ofthe implant. Additionally, with the load removed from the distractionguide, and therefore the inserter, the inserter can also be easilyremoved.

One or more embodiments of an implant insertion instrument 10 forplacement of an implant G into a space between adjacent bony structuressuch as between a pair of adjacent spinal vertebrae are describedherein. The insertion instrument 10 may be used with any type of bonesupport implant G, such as a fusion device, or with alternativeconstructs including but not limited to spacer devices and/or artificialjoint components.

Other features and advantages of the present invention will become moreapparent from the following detailed description, taken in conjunctionwith the accompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purposes of illustration, there are forms shown in the drawingsthat are presently preferred, it being understood, however, that theinvention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 is a right side perspective view of an intervertebral implantinsertion instrument for use in distracting adjacent bony structuressuch as adjacent spinal vertebrae, and/or for inserting an implantand/or transplant of selected size and shape therebetween, in accordancewith one or more embodiments of the present invention;

FIG. 2 is a perspective view of the insertion instrument of FIG. 1 withthe distraction ramps and implant removed;

FIG. 3 is a perspective view of a portion of the insertion instrument inFIG. 2, illustrating an implant carried by distraction guides includingpair of clamp jaw components at a distal end of an elongated inserterbody, in accordance with one or more embodiments of the presentinvention;

FIG. 4 is a perspective view of the insertion instrument of FIG. 2,depicting an implant being grasped by the clamp jaw components, inaccordance with one or more embodiments of the present invention;

FIG. 5 is a perspective view of the insertion instrument of FIG. 4showing the sliding removable mounting of the distraction ramps into thedistraction guides, in accordance with one or more embodiments of thepresent invention;

FIG. 6 is an elevational view of the front of the insertion instrumentof FIG. 5, in accordance with one or more embodiments of the invention;

FIG. 7 is a perspective view of the distal end of the inserter of FIG. 4showing the slideable, removable distraction ramps in an advancedposition in relation to the distraction guides, in accordance with oneor more embodiments of the present invention;

FIG. 8 is a side view of a portion of the insertion instrument of FIG.7, in which the ramp units are in an advanced position, with the distaltips of the ramps inserted into an intervertebral cavity betweenadjacent vertebral bodies, in accordance with one or more embodiments ofthe present invention;

FIG. 9 is side view of a portion of the insertion instrument of FIG. 8in which the distraction guides have been advanced toward theintervertebral cavity, thereby distracting the vertebral bodies, inaccordance with one or more embodiments of the present invention;

FIG. 10 is a side view of a portion of the insertion instrument of FIG.9 in which the distraction guides have been advanced to a final positionin relation to the vertebral bodies and the distraction ramps, inaccordance with one or more embodiments of the present invention;

FIG. 11 is a side view along the elongated midline of the insertioninstrument of FIG. 8, illustrating the lesser height of the implant inrelation to the combined height of the ramp tips and distraction guide,in accordance with one or more embodiments of the present invention;

FIG. 12 is a side elevational view of the insertion instrument depictingthe retraction of a tube member with respect to the ramps and theresulting decrease in the combined height of the distraction ramps inaccordance with one or more embodiments of the present invention;

FIG. 13 is a side view of the insertion instrument of FIG. 12 showingthe engagement of an implant having a height that is greater than thecombined height of the distraction ramps and distraction guides, inaccordance with one or more embodiments of the invention;

FIG. 14 is an elevational view of the insertion instrument of FIG. 13from a vantage point at the left side of the view of FIG. 13 that showsthe distraction guide, implant and clamp jaw components, wherein theguide and jaw components are in an laterally outward position andwherein the distance between the upper and lower outer surfaces of thedistraction ramps is less than the thickness of the implant, inaccordance with one or more embodiments of the present invention;

FIG. 15 is an exploded perspective view of the insertion instrument ofFIG. 1 and an implant suitable for insertion therewith, in accordancewith one or more embodiments of the present invention;

FIG. 16 is a perspective view of an implant insertion instrument for usein distracting adjacent bony structures such as adjacent spinalvertebrae, and for inserting an implant and/or transplant of selectedsize and shape therebetween, in accordance with one or more alternativeembodiments of the present invention;

FIG. 17 is an exploded perspective view of the insertion instrument ofFIG. 16, in accordance with one or more embodiments of the presentinvention;

FIG. 18 is a perspective view of a portion of the insertion instrumentand implant of FIG. 16, with the distraction ramp elements hidden toillustrate the clamp jaw mechanism and the implant, in accordance withone or more alternative embodiments of the present invention;

FIG. 19 is a perspective view of an implant insertion instrument for usein distracting adjacent bony structures such as adjacent spinalvertebrae, and for inserting an implant and/or transplant of selectedsize and shape there between, in accordance with one or more alternativeembodiments of the present invention;

FIG. 20 is an exploded perspective view of the insertion instrument andimplant of FIG. 19;

FIG. 21 is a close-up perspective view of a portion of the insertioninstrument and implant of FIG. 19, with the distraction ramp elementshidden to illustrate the threaded engagement mechanism and the implant,in accordance with one or more embodiments of the present invention;

FIG. 22 is a perspective view of an implant insertion instrument for usein distracting adjacent bony structures such as adjacent spinalvertebrae, and for inserting an implant and/or transplant of selectedsize and shape therebetween, with the distraction ramp elements hiddento demonstrate the threaded engagement mechanism and the implant, inaccordance with one or more alternative embodiments of the presentinvention;

FIG. 23 is an elevational view of the distal end of the insertioninstrument and implant of FIG. 22, demonstrating a compound distractionangle suitable for anterior lateral implant insertion, in accordancewith one or more embodiments of the present invention;

FIG. 24 is a plan view of a portion of the insertion instrument andimplant of FIG. 22 along with a vertebral body, depicting ananterior-lateral approach to implant insertion, in accordance with oneor more embodiments of the present invention;

FIG. 25 is an elevational view of a side of the insertion instrument ofFIG. 22 employing an anterior-lateral approach to implant insertion, andshowing the distraction guide in a final position in relation to thevertebral bodies and the distraction ramps, in accordance with one ormore embodiments of the present invention; and

FIG. 26 is an elevational view of a side of the insertion instrument ofFIG. 25, showing the engagement of an implant having a height greaterthan the combined height of the distraction ramps and the guides, inaccordance with one or more embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a right side perspective view of an intervertebral implantinsertion instrument 10 for use in distracting adjacent bony structuressuch as adjacent spinal vertebrae V1 and V2, and/or for inserting animplant G and/or transplant of selected size and shape therebetween, inaccordance with one or more embodiments of the present invention.

In one or more embodiments, the insertion instrument 10 and relatedimplant G may be adapted for use in spinal surgical procedures forplacement of the implant G into a distracted intervertebral spacewherein the implant G may subsequently serve as a load bearing spacerelement for maintaining a prescribed spacing between adjacent vertebralstructures (or “vertebrae”) V1 and V2. In this regard, the implant G maybe formed from a relatively sturdy and biocompatible material such as(but not limited to) a selected metal or metal alloy, bone, polymer,carbon fiber-reinforced polymer and/or ceramic. The implant G may beformed with a partially open or porous configuration and may be coatedor partially filled with a selected bone ingrowth-enhancing substance,such as autogenous bone material harvested from the patient, withtransplantable allogenic bone material supplied by a third party donor.Such devices, when implanted into the intervertebral space, may promoteingrowth of blood supply and live bone cells from the adjacent spinalvertebrae V1, V2 to inter-knit with the implant G, thereby eventuallyimmobilizing or fusing the adjacent spinal vertebrae V1, V2.

In one or more embodiments, insertion instrument 10 may include handle40 which may include impaction cap 42 at its proximal end, basecomponent 12, tube component 16 which may include flange 18, and knob 20which may include internal threads 62 (FIG. 15) and which may rotateabout shaft 60 having threads 14. Base 12 may include slideable arms 22which may have angled faces 48, which arms 22 may in turn movedistraction guides 36. In one or more embodiments, insertion instrument10 may further include distraction guides 36, which may in turn includeangled faces 44, grooves 38, flat face(s) 50 for contacting an implant,and/or clamp components 46. In one or more embodiments, insertioninstrument 10 may further include distraction ramps (or simply “ramps”)24, which may in turn include stopper (or “stop”) 26, distraction faces28, angled faces 30, flanges 32, and/or depth stops 34.

One or more embodiments of the present invention may be operable toinsert an implant G into an interbody cavity while avoiding impartingany compressive force, or shear force, to the implant until the implantis located in its final position in an interbody cavity, which may be anintervertebral cavity. Moreover, one or more embodiments of the presentinvention may enable the insertion instrument 10 to be extracted fromthe interbody cavity without being subjected to compressive or shearforces from the adjacent bodies during such extraction. Avoidance ofsuch compressive and/or shear forces may enable avoiding damage to theadjacent bodies and/or to the insertion instrument. Further, one or moreembodiments of the present invention may be operable to maintain aninitial angle between the ramps 24 of insertion instrument 10 duringexpansion of the interbody cavity, thereby enabling maintenance of aconstant lordotic angle between the adjacent bodies being separated byinsertion instrument 10. Further, once the implant G is in a finalposition between the adjacent bodies, one or more embodiments of thepresent invention may be operable to gradually transfer the compressiveforce, urging the adjacent bodies together, from the ramps 24 anddistraction guides 36 to the implant, thereby avoiding any suddenundesirable impact forces upon either the implant G or the either or theadjacent bodies.

Insertion instrument 10 may include one or more ramps 24, which mayslide with respect to a mating surface on distraction guides 36, andwhich may be configured for quickly and easily distracting, orseparating, an interbody cavity between two adjacent bodies, or moreparticularly, an intervertebral cavity between two adjacent vertebralbodies. In one or more embodiments, insertion instrument 10 may operateto distract an intervertebral cavity (such as between V1 and V2 in FIG.8) at a substantially optimized insertion and distraction angle forfacilitated placement of the implant G having a height selected from arange of different heights according to individual patient requirements.Moreover, in one or more embodiments, insertion instrument 10 mayprotect the implant G against substantial compression and/or shearforces during intervertebral distraction and implant placement into theintervertebral cavity or “intervertebral space”. In one or moreembodiments, instrument 10 may include at least one removabledistraction guide 36 which may include a pair of clamp components 46 forsecurely supporting and retaining the implant G during intervertebralplacement. Insertion instrument 10 may further include a tube mechanism,or simply “tube”, 16 which may be operationally coupled to the clampcomponents 46 for quickly and easily releasing the implant G within theintervertebral space.

FIGS. 1-5 and 15 depict stages of a method for setting up instrument 10prior to insertion of the implant G in accordance with one or moreembodiments of the present invention. A pair of distraction guides 36may be removably mounted to a pair of slideable arms 22. Distractionguides 36 may be shaped and sized to correspond with the size and shapeof a specific implant G which may be selected for a particular insertionoperation. Distraction guides 36 may configured to match the size andshape of a wide range of possible implants G.

Directing attention to FIG. 15, a portion of base 12 of insertioninstrument 10 may include guide pins 52 which may mate with holes 54 ofslideable arms 22. Base 12 may further include holes 58 into whichsprings 56 may be mounted. Base 12 may further include post 60. Further,knob 20 may include internal threads 62 which may engage threads 14 ofpost 60, and handle 40 may include internal threads 64.

Still directing attention to FIG. 15, arms 22 may move laterally inrelation to the base 12. Otherwise stated, arms 22 may move within aplane parallel to the plane of the serrated upper and lower surfaces ofimplant G in the view of FIG. 15. Arms 22 may move employing slidingcontact with adjacent surfaces, or alternatively using a rollerinterface, or other suitable mechanism for movement of arms 22 withrespect to surfaces remaining stationary within insertion instrument 10.Guide pins 52 on the laterally inward side of arms 22 may reside withinholes 54 on the base 12 to enable the laterally directed motion of thearms 22. A pair of springs 56 (FIG. 15) may be positioned within asecond set of lateral holes 58 in the base 12. This arrangement ofsprings 56 serve to force the arms 22, and thereby the distractionguides 36, out laterally in the absence of any opposing force.

Directing attention to FIG. 2, tube 16 may move with respect to base 12along a longitudinal axis thereof to either open (expand) or close(contract) arms 22. Motion of the tube 16 with respect to the base 12may be effected by rotating threaded knob 20 in the desired direction.Knob 20 may have internal threads 62 that mate with threads 14 on shaft60 on the body 12. Tube 16 may include a cylindrical flange 18 at theproximal end thereof, which may operate to maintain a constant lineardistance between the knob 20 and the tube 16. Employing the apparatusdescribed above, knob 20 may advance or retract the tube 16 into thedesired position with respect to tube 12. As the tube 16 moves towardthe implant G, the internal edges of the tube 16 may engage the angledfaces 48 of the arms 22, thereby bringing the arms together and causingthe distraction guides 36 to grasp the implant G. The knob 20 and thetube 16 may be prevented from retracting too far by threading the handle40 onto the rear of the body 12 using internal threads 64 of the handle40.

In one or more embodiments, distraction guides 36 may be removablyattached to slideable arms 22. Thus, in such embodiments, as the arms 22move laterally inward and outward with respect to the base 12,distraction guides 36 may track the movement of the arms 22. As thedistraction guides 36 move inward, the clamps 46 of the distractionguides 36 may make contact with the lateral walls of the implant G tohold the implant G in place. Furthermore, the flat face 50 of thedistraction guides 36 may press against a proximal wall portion (theportion facing toward instrument 10) of the implant G to ensure properpositioning of the implant. Once the implant G is securely grasped bythe distraction guides 36, the ramps 24 can be slid into position. Themedial face (inner face) of the guides 36 may include one or moregrooves 38 and/or one or more angled faces 44. When viewing insertioninstrument 10 from its distal end (FIG. 6), the angled faces 44 of thedistraction guides 36 may form portions of V-shaped surfaces forengaging corresponding surfaces on ramps 24. In one or more embodiments,each distraction guide 36 may include one upper slanted surface and onelower slanted surface 44 for engaging respective surfaces of ramps 24.The upper and lower faces 44 of distraction guides 36 may be oriented ata generally lordotic angle with respect to one another, whicharrangement may cause the longitudinal axes of the upper and lower ramps24 to also be oriented at this lordotic angle with respect to oneanother. Each of grooves 38 and faces 44 of the distraction guides 36may extend along an axis corresponding to the proximal-distal axis of acorresponding ramp 24. The foregoing may apply to both the upper groove38 and face 44 and the lower groove 38 and face 44 of each distractionguide 36.

Each edge of each ramp 24 may include a flange 32 and angled face 30corresponding to the groove 38 and face 44, respectively, of thedistraction guide 36 with which the ramp 24 edge interfaces. The flange32 of each ramp 24 and the groove of the corresponding distraction guide36 may slide with respect to one another as the ramps 24 move withrespect to the distraction guides 36. The angled faces 30 of the ramps24 may be shaped so as to form a portion of a V-shaped surface with thepoint of the “V” pointed towards the implant G. The ramps 24 may be slidforward until the stops 26 of the ramps 24 make contact with respectiverear portions (portions facing the proximal end of the instrument 10) ofthe guides 36, as shown in FIG. 7. Advancing the ramps 24 with respectto the distraction guides 36 in this manner may operate to present athinner profile for instrument 10, and a more acute angle between (thelongitudinal axes of) the ramps 24. This more acute angle between ramps24 may enable the insertion instrument 10 to more effectively advanceinto a space between adjacent bodies, such as adjacent vertebrae, and tocreate an initial interbody cavity prior to expanding this interbodycavity via movement of the distraction guides with respect to the ramps24.

FIG. 6 depicts the interaction between the implant G, the distractionguides 36, and the ramps 24, in accordance with one or more embodimentsof the present invention. As the flanges 32 of ramps 24 engage thegrooves 38 of guides 36, the angled faces 44 of the guides 36 and angledfaces 30 of the ramps 24 may contact one another. More specifically, theramps 24 may move atop (in the case of the upper ramp 24) the angledface 44 of the distraction guides 36. In FIG. 6, the distraction guides36 are in the medial (inward) position, and may thereby operate to graspthe implant G. The guides 36 may operate to resist any compressive forceoperating to urge the ramps 24 together and to thereby avoid loadingimplant G with any of the compressive force. It is noted that theoverall height of the ramps 24 may be determined by the position of thedistraction guides 36 with respect to the ramps 24 along the lateralaxis of the body 12 (the axis from left to right in the view of FIG. 6).

In one or more embodiments, the ramps 24 may include distraction faces28 on the outer surfaces thereof (the surfaces being configured tocontact the adjacent bodies such as vertebral bodies). The distractionfaces 28 may have surfaces that are roughened in some manner, with oneor more of serrations, knurling, chemical etching, and/or other surfacemodifications. In one or more embodiments, when the distraction guides36 are in the fully inward position, the distance between thedistraction faces 28 of the ramps 24 may be greater than the thicknessof the implant G, which may enable the ramps 24 and the guides 36 toreceive the entirety of the compressive force urging adjacent bodiestogether, thereby shielding the implant from this compressive forceduring the implant insertion process. At the same time, the thickness ofthe implant G may be less than the distance between the inner surfacesof the ramps 24, thereby allowing the ramps to slide over the implantwithout contacting it.

FIGS. 8-14 depict various stages of insertion of the implant G between apair of vertebral bodies V1 and V2 by the insertion instrument 10, inaccordance with one or more embodiments of the present invention. Withreference to FIG. 8, the ramps 24 are in the most extended position withrespect to the distraction guides 36 along the longitudinal axis ofinsertion instrument 10. Additionally, at this stage of the implantinsertion process, the distraction guides 36 may be in the medial(inward) position as shown in FIG. 6. The distraction guides 36 may bemaintained in this medial (inward) position by placing the tube 16 inits most forward or distal position with respect to the body 12. In oneor more embodiments, when the distraction guides 36 are in the medial orinward position, the combined height of the ramps 24 may only slightlyexceed that of the implant G. With this configuration of insertioninstrument 10, the insertion instrument 10 may be advanced toward asurgical site leading with the ramps 24. The distal tips of the ramps 24may be inserted into an intervertebral cavity between a pair ofvertebral bodies V1 and V2 until the depth stops 34 contact the anteriorsurfaces (the surface facing toward the proximal end of insertioninstrument 10) of the vertebral bodies V1 and V2. The entry of the rampsinto the intervertebral cavity may be facilitated by maintaining alordotic angle between the ramps 24 using the distraction guides 36.During the insertion of insertion instrument 10 into the intervertebralcavity, ramps 24 may be prevented from undesirably retracting from theintervertebral cavity by virtue of the presence of frictional forcesbetween distraction faces 28 on the tips of the ramps 24 and thesurfaces of the adjacent vertebrae contacting surfaces 28. The body 12of the device 10 may be advanced toward the vertebral bodies V1 and V2by impacting the impaction cap 42, which may be located at the proximalend of the handle 40.

Having advanced the insertion instrument as a whole toward, and theninto, the intervertebral cavity, it remains to distract, or expand, thecavity. As discussed below, this distraction may be accomplished bymoving the distraction guides 36 distally along the longitudinal axis ofinsertion instrument 10, with respect to the ramps 24 to separate theramps 24. As the instrument 10 advances, the distraction guides 36 mayadvance therewith. The grooves 38 on the medial (inward) side of thedistraction guides 36 may slide along the flanges 32 of the ramps 24.Furthermore, because the angled faces 30 of the ramps 24 may rest onrespective angled faces 44 of the distraction guides 36, the compressiveforce urging the adjacent vertebral bodies together (which may also bereferred to herein as the “load”) may be transferred through the ramps24 to the distraction guides 36. The above-described approach, whichenables the distraction guides 36 to receive all or at leastsubstantially all of the compressive force urging the adjacent bodiestogether, may enable the system and method of the present invention toavoid loading the implant with any of the compressive force from theinterbody cavity during the insertion of the implant into the interbodycavity. The advancement of the distraction guides 36 with respect to theramps 24 distally along the longitudinal axis of the instrument 10 mayoperate to separate the ramps 24 while maintaining the angle between theramps constant. Preferably, the angle between the ramps 24 that is beingheld constant is the lordotic angle suitable for the particularinsertion process being conducted. In one or more embodiments, thepreservation of the angle between the ramps 24 during the insertionprocess may cause the lordotic angle between the surfaces of the bodiesV1 and V2 contacted by the ramps 24 to also remain constant throughoutthe implant insertion process. The above-described approach may provideparallel distraction of bodies V1 and V2 while preserving the desiredlordotic angle between the bodies V1 and V2. This approach contrastswith existing approaches in which ramps or levers pivot about a commonfulcrum, or about separate fulcrums, in which the angle between thesurfaces of the intervertebral cavity is not maintained constantthroughout the implant insertion process.

FIGS. 10 and 11 show the instrument 10 in the fully distracted positionwith the distraction guides 36 and implant G fully advanced into theintervertebral cavity, in accordance with one or more embodiments of theinvention. At the insertion stage shown in FIGS. 10 and 11, the ramps 24may be fully distracted. Still with reference to FIGS. 10 and 11, theimplant G may be located in a desired final location between theadjacent vertebral bodies. The distance between the respectivedistraction faces 28 of the two ramps 24 may be slightly greater thanthe height of the implant G, thereby enabling the serrated faces G1 andG2 of the implant G to be free from contact with the vertebral bodies V1and V2. Thus, at this stage of the insertion process, implant G maystill be free of compressive force from the intervertebral bodies V1 andV2.

FIGS. 12-14 demonstrate the final positioning of the implant G and therelease of the implant G by the instrument 10, in accordance with one ormore embodiments of the present invention. With the implant G in thedesired position along the proximal-distal axis of the instrument 10(the axis from left to right in FIGS. 10-11) in relation to thevertebral bodies V1 and V2, the tube component 16 may be retracted withrespect to the body 12 of instrument 10 toward the proximal end ofinstrument 10. The retraction of tube 12 may be accomplished by rotatingthe knob 20 which may cause the tube 16 to move linearly toward theproximal end of instrument 10 and away from the vertebrae V (where “V”refers to the V1 and V2 together). As the tube 16 is retracted, theinternal springs 56 (see FIG. 15) may cause the arms 22 to move outlaterally away from a longitudinal center of instrument 10, which inturn may cause the distraction guides 36 to move out laterally as well.The lateral motion of the distraction guides 36 away from the center ofinstrument 10 may cause distraction guides to stop receiving, orotherwise stated, to stop resisting the compressive force imparted bythe adjacent bodies V1 and V2. Thus, as the distraction guides 36 moveout laterally, the compressive force from the adjacent bodies, which mayno longer be opposed by the distraction guides, 36 may cause the ramps24 to move toward each other, thereby enabling the vertebral bodies V1and V2 to do the same.

Because the angled faces 30 of the ramps 24 may rest upon thecorresponding angled faces 44 of the distraction guides 36, the ramps 24may comply with the unopposed compressive force from the adjacent bodiesand approach one another by moving into the expanding space between thelaterally displaced distraction guides 36. The approach of the rampstowards one another may continue until the distance between the outerramp 24 surfaces is less than the thickness (or “height”) of the implantG. As the distraction distance of the vertebral bodies V1 and V2diminishes, the compressive force urging the adjacent bodies V1 and V2together may be gradually transferred from the ramps 24 to the implantG. In one or more embodiments, the serrated faces G1 and G2 of theimplant G may engage, or bite into, the endplates (implant-facingsurfaces) of the corresponding vertebral bodies V1 and V2, as the upperand lower bodies V1 and V2 are urged together toward the upper and lowersurfaces, respectively, of the implant G.

The above-discussed approach may enable the gradual transfer of thecompressive force from the ramps 24 to the implant G and may enable theimplant G to be securely held in place during the release of the implantby the instrument 10 and during the extraction of the instrument 10 fromthe intervertebral cavity. The above-discussed approach may also enablethe instrument 10 to be extracted from the intervertebral cavity withoutthe application of a compressive force thereon. Freeing the instrumentfrom the compressive force in this manner, may help avoid damage to theinstrument and/or to the implant during the instrument extraction. Theability to extract the instrument 10 from the interbody cavity whilefree of the application of compressive force from bodies V1 and V2 maybe enabled by the shape of one or more embodiments of the distalportions of ramps 24, as best seen in FIG. 1. In the view of FIG. 1, itmay be seen that the tangs or “finger portions” of the upper ramp 24clear the edges of the implant along the plane of the upper surface ofthe implant. With this arrangement, as the ramps 24 close in on oneanother in response to the compressive force and the gradual removal ofdistraction guides 36, the ramp 24 tangs may move vertically along thesides of the implant G instead of coming to rest on the upper and lowersurfaces of the implant G. In this manner, the ramp 24 tangs may avoidgetting caught between the vertebral bodies and the implant G, as thevertebral bodies come to rest.

It is noted that existing systems and methods commonly includeextracting levers of an instrument from an interbody cavity while acompressive force is still being applied thereto. Such existingapproaches run the risk damaging the instrument during the extractionand/or of damaging the implant by suddenly shifting the compressiveforce from a lip or edge at the distal end of the insertion instrumentto the implant itself as the lip or edge of the instrument clears theproximal edge of the adjacent intervertebral bodies.

FIGS. 16-18 depict a method for setting up an instrument 1610 prior toinsertion of the implant G3 in accordance with one or more alternativeembodiments of the present invention. In one or more embodiments, a pairof distraction guides 1636 may be removably mounted to a pair ofslideable arms 1622. The distraction guides 1636 may be shaped and sizedto correspond with the size and shape of a particular implant G3 whichhas been chosen by a surgeon to conform to an individual patient'sanatomy. Various embodiments of the distraction guides 1636 may beavailable to match various respective implants G3. The slideable arms1622 may move laterally inward or outward in relation to the base 1612,as discussed in connection with the embodiments of FIGS. 1-15. Withreference to FIG. 17, in one or more embodiments, guide pins 1652 on themedial (inward) side of the arms 1622 may be located within holes 1654on the base 1612 to enable the lateral motion of the arms 1622. A pairof springs 1656 may be positioned within a second set of lateral holes1658 in the base 1612. Springs 1656 may operate to force the arms 1622,and thereby the distraction guides 1636, laterally outward from base1612.

Tube 1616 may move along base 1612 employing sliding contact, rollingcontact, or other suitable motion interface. The motion of the tube 1616may be controlled by rotating threaded knob 1620, as discussed inconnection with other embodiments herein. The knob 1620 may includeinternal threads 1662 that mate with external threads 1614 located on ashaft 1660 extending from the base (or “body”) 1612. A cylindricalflange 1618 at the proximal end of the tube 1616, may be operable tomaintain a constant linear distance between the knob 1620 and the tube1616. In one or more embodiments, the above described arrangement mayenable rotation of the knob 1620 to move the tube 1616 to a desiredposition with respect to the body 12. Distal movement of the tube 1616may be operable to force the slideable arms 1622 toward a laterallyinward position. In one or more embodiments, as the tube 1616 movesdistally along the instrument 1610, that is toward the implant G3, theinside edges of the tube 1616 may engage the angled faces 1648 of thearms 1622, thereby pushing the arms 1622 into a laterally inwardposition. The knob 1620 and the tube 1616 may be prevented fromretracting too far with respect to the body 1612 by causing the internalthreads 1664 of handle 1640 to engage the external threads 1614 of thebody 1612.

Since the distraction guides 1636 may be removably attached to theslideable arms 1622, distraction guides 1636 may move laterally alongwith arms 1622. In one or more alternative embodiments, in addition tothe movable distraction guides 1636, a pair of grasping jaws 1668 may beprovided which may move within a cutout 1672 of the guides 1636.Grasping jaws 1668 may also have an angled face 1670 which is engaged bythe tube 1616, as the tube 1616 advances distally with respect to thebase 1612. As the jaws 1668 move laterally inward, the inner walls 1646of jaws 1668 may press against the grooves G4 of the implant G3 tosecurely grasp the implant and to hold the implant in place.Furthermore, the flat faces 1650 of the guides 1636 may press againstthe proximal wall (the wall of the implant facing the proximal end ofthe instrument 1610) of the implant G3 to ensure proper positioning ofthe implant. While the implant G3 is securely grasped by the jaws 1668,the distraction guides 1636 may also be moved laterally inward by thetube component 1616, and the ramps 1624 can be slid into position. Byincorporating the independent grasping jaws 1668 in one or moreembodiments, the implant G3, which may have larger tolerances than theinstrument 1610, may be securely grasped with greater reliability. Upongrasping the implant as described above, the instrument 1610 may conductthe implant G3 insertion operation and subsequent extraction of theinsertion instrument 1610 in much the same manner as described inconnection with FIGS. 8-14.

FIGS. 19-21 depict a method for setting up yet another embodiment of aninsertion instrument, instrument 1910, prior to insertion of an implantG5 into an interbody cavity, in accordance with one or more embodimentsof the present invention. In one or more embodiments, a pair ofdistraction guides 1936 may be removably mounted to a pair of slideablearms 1922. The distraction guides 1936 may be shaped and sized toaccommodate the size and shape of a particular implant G5 which has beenchosen by a surgeon to suit a particular patient's anatomy. A pluralityof distraction guides 1936 may have dimensions that are customized tomatch various respective implants G5. The slideable arms 1922 may movelaterally inward and outward in relation to the base 1912. In one ormore embodiments, guide pins 1952 on the medial side of the arms 1922may be located within holes 1954 on the base 1912 to enable the lateralmotion of the arms 1922. A pair of springs 1956 may be positioned withina second set of lateral holes 1958 in the base 1912. Springs 1956 mayoperate to force the arms 1922, and thereby the distraction guides 1936,laterally outward from base 1912.

Tube 1916 may move along base 1912 employing sliding contact, rollingcontact, or other suitable motion interface. In one or more alternativeembodiments, once the tube 1916 is in a desired position with respect tothe base 1912, the tube 1916 may be locked into place using a lockingarm 1920. The locking arm 1920 may create a friction lock between thebase 1912 and the tube 1916. Movement of the tube 1916 may be operableto force the slideable arms 1922 toward a laterally inward position. Inone or more embodiments, as the tube 1916 moves distally along theinstrument 1910, that is toward the implant G5, the inside edges of thetube 1916 may engage the angled faces 1948 of the arms 1922, therebypushing the arms 1922 into a laterally inward position. The tube 1916may be prevented from retracting too far with respect to the body 1912by inserting the small post 1960 that protrudes from body 1912 into theinternal bore 1964 of handle 1940.

The implant G5 may be attached to the inserter 1910 by means of anelongated shaft 1914. The shaft 1914 may extend through the entire body1912 and handle 1940 of the instrument 1910. The shaft 1914 may includea threaded tip 1918, at the distal end thereof, that may engage theimplant G5 by means of a threaded hole G6 on the proximal side of theimplant. The shaft 1914 may be rotated by a knob 1942 at the proximalend of the shaft 1914. Since the distraction guides 1936 may beremovably attached to the slideable arms 1922, as the arms 1922 movelaterally inward and outward, the distraction guides 1936 may move alongwith the arms 1922. As the distraction guides 1936 move laterallyinward, the inner faces 1950 of guides 1936 may press against theperimeter of the implant G5 and may thereby hold the implant in place.Once the implant G5 is securely held by the threaded shaft 1914, theramps 1924 can be slid into position. The processes of a) assembling theramps 1924 to the instrument 1910 and b) the subsequent insertion of theimplant G5 within an intervertebral cavity are similar to what wasdiscussed in connection with FIGS. 5-14. Accordingly, that discussion isnot repeated in this section.

FIG. 22-26 depict yet another embodiment of the insertion device 2210,in accordance with various aspects of the invention, for placing animplant G5 between two adjacent vertebral bodies V1 and V2 from ananterior-lateral, or oblique, approach. Otherwise stated, the directionof insertion of implant G5 may be at a non-zero angle with respect tothe longitudinal axis of the insertion instrument 2210 about an axisperpendicular the planes of the upper and lower surfaces of implant G5.In one or more embodiments, the non-zero angle may be between 10 and 90degrees. In one or more other embodiments, the non-zero angle may bebetween 15 and 45 degrees. However, in still other embodiments anynon-zero angle between the direction of insertion and the longitudinalaxes of insertion instrument 10 may be employed. In one or moreembodiments, two distraction guides 2220 and 2236 may be removablymounted to two respective slideable arms 2222. Distraction guides 2220and 2236 may be shaped and sized to correspond with the size and shapeof a particular implant G5 which has been chosen by a surgeon to conformto a particular patient's anatomy. Various implementations of thedistraction guides 2220 and 2236 may be made available to match variousrespective specific implants G5. In one or more alternative embodiments,distraction guides 2220 and 2236 may be designed to enable the implantG5 to be inserted from an anterior-lateral approach while maintainingthe appropriate sagittal alignment of the spine. In addition to havingthe grooves 2238 and 2230 and angled faces 2244 and 2232 propagate in agenerally lordotic angle, they are also set at a compound angle, orlateral distraction angle Θ, as shown in FIG. 23. By combining thecompound angle Θ with the distraction angle between the longitudinalaxes of the ramps 2224, the vertebral bodies may be distracted at theappropriate sagittal angle. The sagittal angle of distraction betweenthe vertebral bodies that may be provided by the above combination maybe best seen in FIGS. 25 and 26.

In one or more embodiments, tube 2216 may move along base 2212 employingsliding contact, rolling contact, or other suitable motion interface.Once the tube 2216 is in a desired position with respect to the base2212, the tube 2216 may be locked into place using a locking arm, suchas locking arm 1920 shown in FIG. 19. Motion of the tube 2216 withrespect to the base 2212 may be operable to control the position of theslideable arms 2222 and the distraction guides 2220 and 2236. In one ormore embodiments, as the tube 2216 moves toward the implant G5, theinside edges of the tube 2216 may engage the angled faces 2248 of thearms 2222, thereby pushing the arms 2222 into a laterally inwardposition. In one or more embodiments, the implant G5 may be attached tothe insertion instrument 2210 by means of an elongated shaft 2214. Shaft2214 may extend through the entire body 2212 of the insertion instrument2210. Shaft 2214 may include a threaded tip 2218, at the distal end ofshaft 2214, that may thread into the implant G5 by means of a threadedhole G7 on the anterior-lateral face (a face of the implant G5 facingthe proximal end of the instrument 2210) of the implant G5.

In one or more embodiments, the distraction guides 2220 and 2236 may beremovably attached to the slideable arms 2222. Accordingly, as the arms2222 move laterally, the distraction guides 2220 and 2236 may movelaterally along with the arms 2222. As the distraction guides 2236 movelaterally inward, the inner wall 2250 of each distraction guide 2220,2236 may contact the perimeter of the implant G5 and may thereby operateto hold the implant in place. Once the implant G5 is securely held bythe threaded shaft 2214, the ramps 2224 can be slid into position.Because of the compound angle 8 of the grooves 2238 and 2230 and angledfaces 2244 and 2232, the ramps 2224 are likewise held at this angle Θ.

FIG. 24 depicts the instrument 2210 and implant G5 on a vertebral bodyV2 from an anterior lateral approach, in accordance with one or moreembodiments of the present invention. It is noted that that the implantG5 may be in the same orientation it would have been in, had the implantG5 been implanted from a straight anterior approach, in which theinsertion direction and the longitudinal axis of the insertioninstrument 10 are aligned. Proper orientation of the implant during theinsertion process may be beneficial in ensuring that the proper sagittalalignment of the spine is maintained during and after insertion of theimplant G5. FIG. 24 further shows threaded tip 2218 protruding throughthe sidewall of the implant G5. As the insertion progresses into theintervertebral cavity above the vertebral body V2, depth stops 2234 ofthe ramps 2224 may engage the anterior lateral face of the body V2.

FIG. 25 shows the device 2210 in the fully distracted position betweenthe vertebral bodies V1 and V2 with the distraction guide 2236 and theimplant G5 fully advanced into the intervertebral cavity. At theinsertion stage shown in FIG. 25, the ramps 2224 may be fullydistracted. The implant G5 may be located at a desired final locationbetween the adjacent vertebral bodies. The distance between therespective distraction faces 2228 of the two ramps 2224 may be slightlygreater than the height of the implant G5, thereby enabling the serratedfaces G8 and G9 to be free from contact with the vertebral bodies V1 andV2. Thus, at this stage of the insertion process, implant G5 may stillnot have experienced any compressive force from the vertebral bodies.Furthermore, due to the combination of the angle of distraction of thelongitudinal axes of the ramps 2224 and the compound angle Θ, the ramps2224 may be distracted while being maintained at a constant sagittalangle with respect to one another. It is noted that that the combinationof these angles may match the lordotic angle between the upper and lowercontact surfaces of implant G5 as well.

FIG. 26 demonstrates the final positioning of the implant G5 and therelease of the implant G5 by the instrument 2210, in accordance with oneor more embodiments of the present invention. With the implant G5 in thedesired position in relation to the vertebral bodies V, the tube 2216may be retracted with respect to the body 2212 of instrument 2210. Asthe tube 2216 is retracted, internal springs may cause the arms 2222 tomove out laterally, which may in turn cause the distraction guides 2220and 2236 to move out laterally as well. The outward lateral motion ofthe distraction guides 2220 and 2236 may cause the distraction guides2220 and 2236 to stop receiving, or otherwise stated, to stop resistingthe compressive force imparted by the adjacent vertebral bodies V1 andV2. Thus, as the guides 2220 and 2236 move out laterally, thecompressive force from the adjacent bodies V1 and V2 may cause the ramps2224 to approach one another, thereby enabling the vertebral bodies V1and V2 approach one another as well. Because the angled faces 2240 ofthe ramps 2224 may rest upon the corresponding angled faces 2232 and2244 of the distraction guides 2220 and 2236, respectively, the ramps2224 may comply with the compressive force from the adjacent bodies andmove into the expanding space between the laterally displaceddistraction guides 2220 and 2236. The approach of the ramps toward oneanother may continue until the distance between the outer surfaces 2228of the ramps 2224 is less than the height of the implant G5. As thedistraction distance between the vertebral bodies V1 and V2 diminishes,the compressive force urging the bodies V1 and V2 together may begradually transferred from the ramps 2224 to the implant G5. In one ormore embodiments, the serrated faces G8 and G9 of the implant G5 mayengage, or bite into, the endplates (the implant-facing surfaces) of thevertebral bodies V1 and V2. The above-described gradual transfer ofcompressive force may enable the implant G5 to remain in a desired finallocation between the bodies V1 and V2 without being unintentionallydislodged by the extraction of the insertion instrument 2210. In one ormore embodiments, the shaft 2214 may be unthreaded from the implant holeG7. Upon completion of the above-listed steps, insertion instrument 2210may be removed from the interbody cavity with the implant G5 located inthe desired position with respect to the vertebral bodies V. Asdiscussed in connection with another embodiment herein, variouscharacteristics of insertion instrument 2210 may enable instrument 2210to be free of any compressive force from the bodies V1 and V2 during theextraction thereof from the interbody cavity (in this case, anintervertebral cavity).

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

What is claimed is:
 1. A surgical system comprising: an implant havingopposing sidewalls and a proximal wall, at least one of the walls havinga tool engaging feature; and an insertion tool including: a handle, arod having a first end coupled to the handle and a second end releasablyattachable to the implant, the implant configured to cooperate withlongitudinal advancement and retraction of the rod when attached to therod, an elongate member having a lumen extending therethrough such thatthe rod is longitudinally translatable in the lumen, opposing first andsecond jaws defining an angle, the first and second jaws disposed in adistal region of the elongate member, the implant located between thejaws and longitudinally movable relative to the jaws such that adistance between the jaws increases as the implant is moved distally,and a first mechanism engaging the first and second jaws, the firstmechanism configured to maintain the angle between the first and secondlaws.
 2. The surgical system of claim 1, wherein one of the first andsecond ends of the rod is releasably attached to the tool engagingfeature of the implant.
 3. The surgical system of claim 1, whereindistal movement of the rod results in distal movement of the implant. 4.The surgical system of claim 2, wherein rotation of the handle in afirst direction couples the implant to the rod and rotation of thehandle in a second direction separates the implant from the rod.
 5. Thesurgical system of claim 1, wherein distal ends of the jaws areinsertable between adjacent vertebral bodies.
 6. The surgical system ofclaim 1, wherein the tool engaging feature of the implant is a holedefined through the proximal wall thereof.
 7. The surgical system ofclaim 6, wherein the hole defined through the proximal wall of theimplant is a threaded hole.
 8. The surgical system of claim 7, whereinthe second end of the rod is threaded and configured to thread into thethreaded hole to releasably attach the rod to the implant.
 9. Aninstrument for inserting an implant, comprising: a first ramp includinga first vertebral contact surface and having a first longitudinal axisbetween proximal and distal ends thereof; a second ramp including asecond vertebral contact surface and having a second longitudinal axisbetween proximal and distal ends thereof, the first and second rampsdefining an angle between the first and second ramps; a first mechanismengaging the first and second ramps, the first mechanism configured tomaintain the angle between the first and second ramps; and a secondmechanism including a rod having a first end coupled to a handle and asecond end releasably attachable to the implant, the implant configuredto cooperate with longitudinal advancement and retraction of the rodwhen attached to the rod, an elongate member having a lumen extendingtherethrough such that the rod is longitudinally translatable in thelumen, the second mechanism operable to advance the implant between theramps toward the distal ends of the first and second ramps such that adistance between the first and second ramps increases as the implant ismoved distally, the first mechanism maintaining the angle between thefirst and second ramps as the first and second ramps separate duringdistal advancement of the implant.
 10. The insertion instrument of claim9, wherein the angle is a non-zero angle.
 11. The insertion instrumentof claim 9, wherein the separation of the first and second rampsoperates to provide distraction of adjacent bodies while maintaining alordotic angle between the adjacent vertebral bodies.
 12. The insertioninstrument of claim 9, wherein the first and second vertebral contactsurfaces are sized and shaped to engage adjacent vertebral bodies of anintervertebral cavity.
 13. A method for inserting an implant into anintervertebral cavity between adjacent vertebral bodies, the methodcomprising: coupling the implant to an implant insertion instrument, theinsertion instrument including: a first ramp having a first longitudinalaxis between proximal and distal ends thereof; a second ramp having asecond longitudinal axis between proximal and distal ends thereof, thefirst and second ramps defining an angle therebetween; a rod having afirst end coupled to a handle and a second end releasably attachable tothe implant, the implant configured to cooperate with longitudinaladvancement and retraction of the rod when attached to the rod; anelongate member having a lumen extending therethrough such that the rodis longitudinally translatable in the lumen; a mechanism for maintainingthe angle between the first and second ramps; inserting respectivevertebral contact surfaces of the first and second ramps into anintervertebral space; and advancing the rod through the lumen of theelongate member to advance the implant between the first and secondramps such that a distance between the first and second ramps increasesas the implant is moved distally and the first and second ramps separateto distract the vertebral bodies, the mechanism for maintaining theangle between the first and second ramps holding the angle constant asthe first and second ramps separate.
 14. The method of claim 13 furthercomprising continuing the advancement such that the implant is receivedinto the intervertebral cavity.
 15. The method of claim 14 furthercomprising disengaging the implant from the rod.
 16. The method of claim15 further comprising withdrawing the distal ends of the first andsecond ramps from the intervertebral space.
 17. The method of claim 13wherein the angle corresponds to a lordotic angle.
 18. The method ofclaim 13 wherein the separation of the first and second ramps causesseparation of the vertebral bodies while maintaining the lordotic anglebetween the vertebral bodies.
 19. The surgical system of claim 1,wherein the angle is a non-zero angle.